This invention relates to lasers and, more particularly, to lasers which emit at more than one wavelength.
There are many applications requiring high efficiency, wavelength diverse lasers particularly relating to tactical military scenarios. Presently, the availability of such lasers is at a minimum. One approach has been to use second harmonic generation. For example, lasers employing Nd.sup.+3 as the active ion lase at 1.06 microns. Some degree of an added frequency option lies in the use of the 1.06 micron laser "doubled" to 0.53 microns through second harmonic generation. This approach suffers from (1) the material limitations on all the optical components involved, since nonlinear conversion requires high peak powers, and (2) the basic inefficiency of the doubling process.
Another approach has been to employ two cavities having a common optical leg, each of which is tuned to a different transition of the laser medium employing a single active ion such that when the laser emits two different wavelengths each cavity will generate laser pulses at the respective wavelengths. This technique requires great care in the critical selection of the laser medium which must generate substantial amount of energies at distinct wavelengths.